1. Field of the Invention
The present invention relates to a storage container for a liquid chlorosilane, and a closing lid for the storage container.
Priority is claimed on Japanese Patent Application No. 2008-208320, filed Aug. 13, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
Chlorosilanes, such as trichlorosilane or silicon tetrachloride, are used for semiconductors, such as polycrystalline silicon and epitaxial films on silicon wafers, and for the raw materials of optical fibers, and the like. Typically, chlorosilanes are filled into containers or cylinders in manufacturing factories, and are carried to and used in manufacturing factories of semiconductors, optical fibers, or the like. When the chlorosilanes react with moisture in the air or the like, corrosive gas and silica are generated. Since the corrosive gas and silica corrode facilities, thereby causing problems, such as causing deterioration of quality and clogging of pipes, chlorosilanes stored the container must be prevented from contacting air or moisture.
As proposals which prevent the chlorosilanes in a container from contacting air, for example, closing structures as described in Japanese Patent Unexamined Publication Nos. 5-231598 and 2008-116044 are conventionally adopted.
In a gas-filled container of Japanese Patent Unexamined Publication No. 5-231598, in order to prevent silane gas leaked when a valve is loosened from igniting spontaneously in air, contaminating a mouthpiece, or corroding the mouthpiece or a gas supply system, a cap which airtightly seals the mouthpiece is provided, and an adsorbent which adsorbs moisture and oxygen, or an adsorbent which adsorbs silane gas is provided in this cap. Japanese Patent Unexamined Publication No. 5-231598 describes that, since the atmosphere in the mouthpiece and the cap is replaced with an inert gas composed mainly of nitrogen gas or the like by this adsorbent, corrosion can be suppressed even if the silane gas leaks out.
A leak control device in which a leaked reactive gas can be collected by providing a containment enclosure so as to enclose a fluid flow part connected to an outlet opening of a container is described in Japanese Patent Unexamined Publication No. 2008-116044.
However, the techniques of Japanese Patent Unexamined Publication Nos. 5-231598 and 2008-116044 which have the prevention of gas leaks as their object cannot be applied to storage containers of liquid chlorosilanes.
For example, in the gas-filled container of Japanese Patent Unexamined Publication No. 5-231598, absorption cannot be made by an adsorbent when liquid chlorosilane is leaked. Further, an apparatus of Japanese Patent Unexamined Publication No. 2008-116044 is an effective means in regard to leaks in a pipe connecting portion, but is not an effective means when there are leaks caused by deterioration of sealing performance of a valve.
Particularly, when the chlorosilanes contact air, they react with the air, thereby generating rust on a valve or silica adhere to the valve which obstructs the operation of the valve. When the end of a valve is sealed by a closing lid, the air including moisture exists in the sealed space formed between the valve and the closing lid. Therefore, when the leak of the chlorosilanes is caused by deterioration of sealing performance of the valve, the inside of the valve is corroded by the reaction with the moisture.
The present invention was made in view of such a situation, and the object thereof is to provide a storage container for a liquid chlorosilane and a closing lid for the storage container which can maintain the soundness of a valve with simple structure and reliably prevent the generation of corrosive gas caused by the leaking of its contents.